Synthesis and antiplatelet, antiinflammatory and antiallergic activities of 2,3-disubstituted 1,4-naphthoquinones.

Modification of 2-acetamido-3-chloro-1,4-naphthoquinone, which has potent antiplatelet, antiallergic and antiinflammatory activities, led to a series of 2,3-disubstituted 1,4-naphthoquinones. Some of these compounds showed significant antiplatelet, antiallergic and antiinflammatory activities. Among them, 2-methoxy-3-chloro-1,4-naphthoquinone (15) and 2-ethoxy-3-chloro-1,4-naphthoquinone (17) exhibited potent inhibitory effects on neutrophil and mast cell degranulation. 2-Methoxy-1,4-naphthoquinone (20) and 2-ethoxy-1,4-naphthoquinone (21) exhibited potent inhibitory effect on neutrophil superoxide formation. These four compounds were thus selected for further evaluation.